Table 1.

Depletion of endogenous GTP markedly attenuates glucose-induced ROS generation in INS 832/13 cells

Condition	Degree of ROS Generation, fold over basal glucose
Low glucose	1.00
High glucose	1.58 ± 0.06†
Low glucose + mycophenolic acid	1.08 ± 0.02*
High glucose + mycophenolic acid	1.16 ± 0.04‡
Low glucose +cyclosporine A	1.06 ± 0.09*
High glucose + cyclosporine A	1.46 ± 0.14†
Low glucose + rapamycin	1.05 ± 0.08*
High glucose + rapamycin	1.42 ± 0.15†

Values are means ± SE from three independent experiments in each case. INS 832/13 cells were incubated with low glucose (2.5 mM) and low serum in the presence or absence of mycophenolic acid (10 μM), cyclosporine-A (5 μM), and rapamycin (100 nM) for 24 h. Following this, cells were stimulated either with low (2.5 mM) or high glucose (20 mM) for 1 h in the continuous presence and or absence of the inhibitors, as indicated. At the end of stimulation, cells were incubated with 2′,7′-dichlorofluorescein diacetate (10 μM) for 30 min and harvested for dichlorofluorescein fluorescence. ROS generated was quantified as dichlorofluorescein fluorescence and expressed as arbitrary units.

^*No significant difference vs. low glucose alone.

^†P < 0.05 vs. low glucose alone.

^‡P < 0.05 vs. high glucose alone.